Seminal hyperviscosity is associated with poor outcome of controlled ovarian stimulation and intrauterine insemination: A prospective study

Objective-To determine the relationship between seminal hyperviscosity and pregnancy outcome in patients undergoing ovarian hyperstimulation and intrauterine insemination (IUI). Methods-Patients were enrolled in the study between October 2002 and December 2003 at the Toronto Centre for Advanced Reproductive Technology. This was a prospective trial that included 37 infertile couples with abnormal seminal viscosity who underwent 57 insemination cycles as treatment for infertility (group I) and 37 couples undergoing 51 IUI cycles during the same time period, with normal semen viscosity, who served as controls (group II). Cycles were stimulated using either gonadotropin (FSH) only or FSH combined with an aromatase inhibitor, and raw semen processed for intrauterine insemination using swim-up or density gradient. Results-The mean number (+/- SD) of IUI cycles was 1.93 +/- 1.42 per patient (range 1 to 7 cycles) in group I and 2.4 +/- 1.05 (range 1 to 4) in group II. The overall pregnancy rate (PR) was 14 % (8/57) and 11.8 % (6/51) per cycle, and 21.6% (8/37) and 16.2% (6/37) per patient in group I and in group II, respectively. Among patients where the male had seminal hyperviscosity, five (62.5%) pregnancies miscarried in the first trimester; there was no miscarriage in the control group. Conclusion: The high miscarriage rate in couples with semen hyperviscosity may be attributed to biophysical alterations or chemical changes of the ejaculate that could impact sperm quality despite normal sperm parameters on semen analysis.